An angular ball bearing is provided which can suppress runout of a retainer during high-speed rotation. A retainer of a synthetic resin is mounted between an outer ring and an inner ring, and balls are housed in pockets formed in the retainer. The pockets are cylindrical. Conical guide surfaces are formed on the cylindrical inner surface of each pocket at its inner-diameter end in the circumferential direction of the retainer. The radius of curvature of the conical guide surfaces at the large diameter ends thereof is greater than the radius of curvature of the cylindrical inner surfaces, thereby preventing the contact points between the balls and the conical guide surfaces from becoming markedly displaced in the diametric direction during high-speed rotation, and thus suppressing runout of the retainer.